Just swapped my tpi to carb. I just took this carb off a motor that was running great. Bolted it on my motor and it wont idle at all. I can barly tap the throttle and it will run then die after 1 second unless I tap it again. It seems like its running out of fuel I think?
Everything I searched for looks really hard to read and complicated.
When I rev the motor it does great, but as soon as i let completly off the gas it stalls then dies.

I havent been able to set my timing yet so i dont know what its set at.
thanks

You could remove all but the necessary vacuum lines to make sure it's not an issue and then go from there. I know when I used all new vacuum lines on mine they didn't seal very well. I had to buy all new hose from a different store. Also check the carb and manifold to make sure there aren't any open ports.

Have you tried just turning the idle speed up and/or richening the idle mixture? If your engine wants more fuel, then just give it more fuel. You really need to properly tune the carb to match your engine. An untouched smogger truck carb on a big cammed motor is just not ideal.

I'd first start by rreplacing the Thumper cam with one that'll give you a better idle, more fuel economy, AND more power.

I turned the idle mixture screws all the way out and the idle screw is all the way in. It will barly idle like this.
If I put my hand over the top of the carb and restric the airflow it idles WAAAAY up. Is there anyway to make this thing get more fuel?!? Im gonna go try and turn my pressure up.
ALso when driving it down the road it will run good from about 2500 to around 3500 then it will sputter. then it will REALLY MOVE from around 4000 to about 6000... :-)
from 4000+ this thing fells like if I had the tpi on it still and just hit a 100shot of Nitrous!

well it wont be as loud when you get the rest of the exhaust on . . . and i'm still tryin to figure out why you downgraded from a TPI to a carb but to each their own.

btw you should've looked for a t-5 or t-56 trans to control that idle, do you have a stall yet for that thing? stock stall speed wont work for a bigger cam compared to stock size . . . i'm assuming it's the same with the stall in 3rd gens like it is with the stalls in 4th gens

I don't think stall speed is his issue yet. Of course, I'm assuming he's trying to get it to idle in Park or Neutral and I've been wrong before...

__________________ "A man who voluntarily drives a car like that and still manages to maintain such impervious confidence that it will faithfully start the next time he turns that key is an encouragement for us all to take greater risks in life."

I sprayed all around the intake and under the carb with brake cleaner to chek to leaks and I got nothing. The stall will need to be changed but I havent even put it in gear yet with it idling so thats not my problem at the moment.
The TBI motor with L98 heads should be exactly the same as a L98.
It has the same pistons anyways, only differance is no roller cam.
From everything I have found and read the Qjets run very lean at idle stock. So now I have much lower vacume and im sucking in alot more air and it seems like its just to lean to idle for more than about 2 or 3 seconds.

I sprayed all around the intake and under the carb with brake cleaner to chek to leaks and I got nothing. The stall will need to be changed but I havent even put it in gear yet with it idling so thats not my problem at the moment.
The TBI motor with L98 heads should be exactly the same as a L98.
It has the same pistons anyways, only differance is no roller cam.
From everything I have found and read the Qjets run very lean at idle stock. So now I have much lower vacume and im sucking in alot more air and it seems like its just to lean to idle for more than about 2 or 3 seconds.

on my 2000 with that slightly larger cam and the stock stall, it would fall on it's face park . . . i'm still leaning towards the stall.

Qjets run very lean when the idle mixture screws are turned in and many were set intentionally lean at the factory with tamper proof plugs over the screws. I 'assume' you've removed the tamper proof plugs?

Have you capped EVERY vacuum port on the carb and manifold, including the brake booster, etc.? Have you clocked the dist a little each way-or have a buddy turn it while you're keeping it running with the throttle?

__________________ "A man who voluntarily drives a car like that and still manages to maintain such impervious confidence that it will faithfully start the next time he turns that key is an encouragement for us all to take greater risks in life."

A 1979 q-jet was an emmissions tuned carb. With the cam you are running you will need to enlarge the idle down tubes and the orifaces in the primary side that "sense" the air being pulled into the engine. Also the throttle shaft is probably worn out, allowing air to bypass the throttle plates. On a small cam you wont see much of a difference but on the engine you have now, I think you would notice. Buy a book called " cliff Ruggles" How to build and modify a rochester q-jet for performance" It is a great book that is easy to follow. I have a sbc with a mild summit K1103 cam. I had to rework my carb to get it to idle well. I have a wide band A/F monitor and it idles at 13.7:1 now. If you are going to keep the q-jet take the time to learn how they work and you'll be surprised at how easy, and inexpensive tuning them can be.

All valid, but I would think he should be able to get it to idle, even if it's a rough idle without opening it up. It was reported to have worked perfectly on another, albeit less aggressive, motor. Even with the motor combo I'd think a rough idle at 800-1000 rpm should be possible with a "known good" qjet.

I'd get the motor running then open up the qjet to tune the quality of the idle. I fear the main prob here is outside the carb...

__________________ "A man who voluntarily drives a car like that and still manages to maintain such impervious confidence that it will faithfully start the next time he turns that key is an encouragement for us all to take greater risks in life."

Well I have checked and checked for vacume leaks, I cant find any at all..
This cam just doesnt have much vacum at idle and the carb isnt dumping enough fuel. If the car was only going dead when I put it in gear then I would deffinantly agree that the stall would be a big issue. The carb was running perfect on the stock cam and stock 76cc swirl port heads. I duno if I wanna mess with having to customize this carb or just save up for a holley.
If anyone has a good writeup on customizing these qjets (other than buying a book) with lots of pictures That would deffinantly help!
Thanks for all the input guys

lol im only running a 550 cfm holly....been a while since i put the cam in...got a high rise edelbrock performance rpm intake and some headers mwahahah....i like it...need more...glad to hear you got a carb that works...i would of checked if the carb needed rebuilt...my holly blew the secondary circuits lol

Yea I know it was way off. I just couldnt find a way to adjust it without drilling and enlarging stuff.. I would have ****ed it up if i tried to do that. Atleast I can sell it now and get some of my money back. I got the holley for $150 so total I have about $600 in my whole motor and I know its pushing atleast 300hp. Ill probly add a 100 shot later after I get exhaust on it and a stall/shift kit.